1. Field of the Invention
The present invention relates to an automatic storage system. More particularly, the present invention relates to an automatic storage system for storing articles at a stage between a carrying apparatus and a processing apparatus.
2. Background Information
In a manufacturing plant for semiconductor devices or liquid crystal devices, semiconductor devices or liquid crystal devices are formed on substrates, e.g., silicon wafers or glass plates, using such processes as thin film deposition, oxidation, and etching. Between such processes, substrates are stored in cassettes (which are an example of an “article”) and the cassettes are moved by automated guided vehicles. A buffer called a front automatic storage system is provided in a transfer area between a processing apparatus and a carrying apparatus in order to adjust a processing time between the carrying apparatus and the processing apparatus (e.g., see Japanese Laid-open Patent Publication No. 2001-298069).
A conventional front automatic storage system has a plurality of shelves arranged with vertical spaces in-between and configured for storing cassettes and a transferring apparatus contrived to transfer articles between shelves.
The shelves are arranged vertically with spaces in-between, and the uppermost shelf serves as a cassette transfer area where cassettes are transferred to and from an automatic guided vehicle serving as a carrying apparatus. A cassette transfer port through which substrates are transferred to the processing apparatus is arranged below the bottommost shelf. At the transfer port, the processing apparatus extracts substrates from the cassette so that the substrates can be processed by the processing apparatus.
The transferring apparatus is arranged facing an opposite side of the shelves as the processing apparatus and is contrived to transfer cassettes between shelves and between a shelf and the transfer port.
By providing such a front automatic storage system, cassettes can continue being carried in and out and the system can be prevented from going down even when the supply or carrying away of cassettes is interrupted due to troubles with the processing apparatus or the carrying apparatus.
With a front automatic storage system like that described above, the front automatic storage system gets in the way when maintenance is performed on the processing apparatus and the transfer port of the processing apparatus. Thus, during maintenance, the front automatic storage system needs to be removed. With a conventional front automatic storage system, there is a possibility that the time required for removing and reattaching the front automatic storage system will cause the idle time of the processing apparatus to be long.